Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
  • A23L5/40—Colouring or decolouring of foods
  • A23L5/49—Removing colour by chemical reaction, e.g. bleaching
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L19/00—Products from fruits or vegetables; Preparation or treatment thereof
  • A23L19/10—Products from fruits or vegetables; Preparation or treatment thereof of tuberous or like starch containing root crops

Definitions

• the present invention relates to a process for manufacturing bleached vegetable pulps, more particularly vegetable pulps for food use bleached using hydrogen peroxide in an alkaline aqueous solution.
• the vegetable pulps whose bleaching is targeted by the present invention are for example those of sugar beet or not, citrus fruits such as peach, pear, apple, apricot, oilseeds like sunflower, cereals like wheat , corn or oats, vegetables such as peas, after the product normally recoverable from each of them, such as sugar, fruit juice, pectin, oil, starch, flour, has been extracted in a known manner.
• extracted pulps which constitute the basic plant material for which the process of the present invention is intended, are designated in all that follows by the single term of pulp, unless specified.
• dietary fibers are characterized by a high content of dietary fiber, which can be determined by known enzymatic method.
• the present invention makes it possible, contrary to known methods, to obtain pulp which is really bleached, with a high degree of whiteness for the technical field concerned.
• the pulp is used in the form of an aqueous suspension of the vegetable material of greater or lesser consistency.
• the consistency is expressed by the concentration of vegetable matter counted in the dry state expressed in percent by weight.
• the first step can be carried out for example in a high density mixer known in the paper industry or in a machine essentially consisting of two helical surfaces penetrating into each other, wound around parallel shafts, driven in synchronous rotation in the same direction inside a sheath enveloping them, and determining from upstream to downstream in the direction of advancement of the material a succession of zones for driving and braking the material, described by example in the French patents published under the numbers 2319737, 2418295, 2451963 and the French certificate of addition published under the number 2436844, and marketed for example by the French company CLEXTRAL under the name of "BI-VIS".
• the duration of this first stage is generally less than 1 minute, . washing is normally carried out with water, at a temperature preferably between 20 ° C and 60 ° C,
• washing means the operation of removing a certain percentage of the liquid phase present in the pulp before washing.
• the washing efficiency is reflected by this percentage. It is here preferably equal to or greater than 90%.
• Washing usually consists of a repeated sequence of diluting the pulp and spinning it most often by filtration or pressing.
• a "BI-VIS" type machine as described above is well suited for its execution.
• the stabilizing agent for hydrogen peroxide is chosen more often in practice among sodium silicate, magnesium in the form of magnesia or in the form of soluble salt such as chloride or sulfate.
• the sodium silicate is conveniently used in the form of an aqueous solution with a density equal to 1.33. It is the quantity of this solution which is expressed when reference is made in all that follows to sodium silicate.
• the amount of sodium silicate, like that of any reagent in all that follows is expressed in percent by weight relative to the vegetable material counted in the dry state. It is here most often between approximately 0.5% and 6%, preferably between 2% and 4%.
• the alkaline agent generally added to hydrogen peroxide is the sodium hydroxide used most often in an amount of between about 2% and 5%. AT As an indication, the pH after the action of hydrogen peroxide is generally less than 8.5 for most pulps.
• the method of the invention can be carried out for example in an equipment consisting of the succession of the following main apparatuses: a first machine of the "BI-VIS” type in which the pulp is mixed with the acid under the conditions of treatment in an acid medium, a residence capacity, a second machine of the "BI-VIS” type in which the washing of the pulp which has been treated in an acid medium and the mixing of the washed pulp with hydrogen peroxide are carried out successively and the products which accompany it under the conditions of action of hydrogen peroxide, a residence capacity.
• a first machine of the "BI-VIS" type in which the pulp is mixed with the acid under the conditions of treatment in an acid medium
• a residence capacity a second machine of the "BI-VIS” type in which the washing of the pulp which has been treated in an acid medium and the mixing of the washed pulp with hydrogen peroxide are carried out successively and the products which accompany it under the conditions of action of hydrogen peroxide, a residence capacity.
• the initial pulp, before treatment in an acid medium, can advantageously be washed with water to remove it from foreign bodies such as sand.
• the pulp After having been subjected to the action of hydrogen peroxide, the pulp is preferably brought to a pH of between approximately 5 and 6 by means of an acid agent such as sulfur dioxide in aqueous solution, so as to improve conservation or storage, then wash and dry for use.
• an acid agent such as sulfur dioxide in aqueous solution
• a sugar beet pulp from which the sugar has been extracted which is in the form of an aqueous suspension whose pH is equal to 6, whose consistency is equal to 5% and which contains 10 kg of vegetable material per liter. 'dry state, is brought to pH equal to 2 by addition of 540 g. sulfuric acid 96% by weight, and stirred at this pH for 20 minutes at a temperature equal to 35 ° C before being filtered and washed with water on a vibrating sieve with a washing efficiency equal to 90%.
• the pulp thus washed is taken from the filter and brought to a consistency of 10% to be subjected, with stirring, to the action of 0.715 kg of an aqueous solution of hydrogen peroxide at 70% by weight of peroxide, of 1 kg d '' an aqueous solution of sodium hydroxide at 20% hydroxide, and 0.4 kg sodium silicate, for 2 hours at 60 ° C.
• the pH of the pulp after these 2 hours is 6.8.
• the pulp is then brought to pH 6 using sulfur dioxide in aqueous solution, then filtered, washed and dried. It finally leads, after grinding into grains with a dimension of less than 100 ⁇ m, to a white flour of appearance and whose weight corresponds to more than 80% of the weight of the starting pulp counted in the dry state.
• the degree of whiteness of this flour measured on sintered pellets in ISO white degree according to the ISO standard of the paper industry, is equal to ISO 41.5 ° while the starting pulp has a degree of white measured in the same conditions only equal to ISO 34 °.
• a corn pulp or grain, residue of the corn after extraction of the starch, whose consistency is equal to 9.8% and which contains 7.9 kg of vegetable matter in the dry state, is brought to pH equal to 2 , 1 by addition to the pulp of 274 g of 96% sulfuric acid, then stirred at this pH for 30 minutes at 30 ° C, before being washed with an efficiency greater than 90% and then subjected to action stirring 0.63 kg of an aqueous solution of hydrogen peroxide containing 70% peroxide, 0.88 kg of an aqueous solution of sodium hydroxide containing 20% hydroxide, and 0.352 kg of silicate sodium, for 2 hours at 60 ° C. After these 2 hours the pH is 7.5.
• the milled corn pulp finally obtained has a degree of whiteness equal to 43 ° ISO while it was only equal to 30 ° ISO for the starting pulp.
• the degree of whiteness of the bleached pulp is equal to ISO 46 °.
• this degree of white is only 38 ° ISO and the flour obtained is yellow.
• the degree whiteness of the bleached pulp is equal to ISO 45 °.
• Example 2 By operating as in Example 1 but with a beet pulp of initial white degree equal to ISO 37 °, carrying out the treatment of the pulp in an acid medium to a consistency equal to 2% and by making the peroxide act. hydrogen on the pulp washed at a rate of 10% of hydrogen peroxide counted in 100% with 4% of sodium hydroxide counted in 100%, the pH after action of hydrogen peroxide is equal to 7.6 and one obtains a bleached pulp with a white degree equal to ISO 53 ° while only 44% of the hydrogen peroxide used is consumed.
• the weight of bleached dry matter is equal to 80% of the initial vegetable matter in the dry state.

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• Chemical & Material Sciences (AREA)
• Food Science & Technology (AREA)
• Health & Medical Sciences (AREA)
• Nutrition Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Polymers & Plastics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Paper (AREA)
• Storage Of Fruits Or Vegetables (AREA)
• Coloring Foods And Improving Nutritive Qualities (AREA)
• Seasonings (AREA)
• Fodder In General (AREA)

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• 1989
  • 1989-06-05 FR FR8907624A patent/FR2647641B1/fr not_active Expired - Lifetime
• 1990
  • 1990-05-31 EP EP90420262A patent/EP0402280B1/fr not_active Expired - Lifetime
  • 1990-05-31 DE DE9090420262T patent/DE69000790T2/de not_active Expired - Fee Related
  • 1990-05-31 DK DK90420262.9T patent/DK0402280T3/da active
  • 1990-06-05 CA CA002018281A patent/CA2018281C/fr not_active Expired - Fee Related
  • 1990-06-05 JP JP14719090A patent/JPH0671415B2/ja not_active Expired - Lifetime
  • 1990-06-05 NO NO902471A patent/NO176742C/no not_active IP Right Cessation
  • 1990-06-05 US US07/533,516 patent/US5094866A/en not_active Expired - Fee Related

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